Method and system for producing cyclohexane hydrogen peroxide by oxidation of cyclohexane

Abstract

This invention provides a method and system for producing cyclohexyl hydrogen peroxide by cyclohexane oxidation. The method includes the following steps: reacting cyclohexane with an oxygen-containing gas containing CO2 to obtain a material containing cyclohexyl hydrogen peroxide. The method of this invention improves the yield and selectivity of cyclohexyl hydrogen peroxide by reacting the feed cyclohexane with an oxygen-containing gas containing CO2, reduces production costs, requires less equipment investment, and has a simple operation process. It can be used in the continuous industrial production of cyclohexane to cyclohexyl hydrogen peroxide via air oxidation.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method and system for the oxidation of cyclohexane to produce cyclohexyl hydrogen peroxide. Background Technology

[0002] The air oxidation process of cyclohexane first produces cyclohexyl hydrogen peroxide, which is then further oxidized to yield cyclohexanol and cyclohexanone, ultimately producing adipic acid. Cyclohexyl hydrogen peroxide, as an intermediate product, is commonly used in the decomposition to prepare cyclohexanol and cyclohexanone, and can also be used to synthesize high-value-added organic chemicals.

[0003] Production experience shows that in the preparation of cyclohexane alcohol and cyclohexanone from cyclohexane, a 1% increase in cyclohexane conversion leads to a decrease in the selectivity of the target product by approximately 4%. Therefore, increasing the cyclohexane conversion rate will decrease the selectivity of the target product, as described in Chinese Patent Application No. 200610031809.6. For example, Chinese Patent Application No. 201610730291.9 discloses a method for preparing cyclohexane alcohol and cyclohexanone. This method first oxidizes cyclohexane with oxygen-containing gas to generate an oxidizing liquid containing cyclohexyl hydrogen peroxide, and then extracts the oxidizing liquid with a strong alkaline solution to obtain an alkaline aqueous phase containing cyclohexyl hydrogen peroxide and a cyclohexane organic phase. In this method, the cyclohexane conversion rate needs to be controlled within a low range (0.5%–1.5%).

[0004] Therefore, the cyclohexane conversion rate in existing cyclohexane oxidation routes is low (3-5%), and the selectivity of cyclohexylhydrogen peroxide is also low (5%), usually occurring as a byproduct. Clearly, new methods are necessary to obtain large quantities of cyclohexylhydrogen peroxide. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for producing cyclohexyl hydrogen peroxide by oxidizing cyclohexane. This method improves the yield and selectivity of cyclohexyl hydrogen peroxide by reacting cyclohexane with an oxygen-containing gas containing CO2, reduces production costs, requires less equipment investment, and has a simple operation process. It can be used in the continuous industrial production of cyclohexyl hydrogen peroxide by air oxidation of cyclohexane.

[0006] In a first aspect, the present invention provides a method for oxidizing cyclohexane to produce cyclohexyl hydrogen peroxide, comprising the following steps:

[0007] Reacting oxygen-containing gas containing CO2 with cyclohexane yields a material containing cyclohexyl hydrogen peroxide.

[0008] Furthermore, in the oxygen-containing gas containing CO2, the volume ratio of CO2 to O2 is (2-15):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 13:1, 15:1 or any value between them.

[0009] Furthermore, in the oxygen-containing gas containing CO2, the volume ratio of CO2 to O2 is (3-10):1.

[0010] Furthermore, in the oxygen-containing gas containing CO2, the volume concentration of CO2 is 30-60%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60% or any value between them.

[0011] Furthermore, in the oxygen-containing gas containing CO2, the volume concentration of O2 is 3-15%, for example, 3%, 4%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 10%, 12%, 14% or any value between them.

[0012] Furthermore, in the oxygen-containing gas containing CO2, the volume concentration of O2 is 5-9%, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9% or any value between them.

[0013] Furthermore, the oxygen-containing gas containing CO2 also includes an inert gas.

[0014] Furthermore, the inert gas is selected from nitrogen and / or argon.

[0015] Furthermore, the mass ratio of the oxygen-containing gas containing CO2 to cyclohexane is (3-15):1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1 or any value between them.

[0016] Furthermore, the mass ratio of the oxygen-containing gas containing CO2 to cyclohexane is (3-8):1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any value between them.

[0017] Furthermore, the reaction temperature is 130-200°C, for example, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or any value between them.

[0018] Furthermore, the reaction temperature is 150-170°C, for example, 150°C, 153°C, 156°C, 159°C, 162°C, 165°C, 168°C or any value between them.

[0019] Further, the pressure of the reaction is 0.9-1.5 MPa, for example 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa or any value between them.

[0020] Furthermore, the reaction pressure is 1.0-1.2 MPa.

[0021] Furthermore, the reaction time is 1-20 min, for example, 1 min, 5 min, 10 min, 12 min, 15 min, 17 min, 20 min or any value between them.

[0022] Furthermore, the reaction time is 2-10 min, for example, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value between them.

[0023] In a second aspect, the present invention provides a system for the oxidation of cyclohexane to produce cyclohexyl hydrogen peroxide, which is used in the method described in the first aspect of the present invention, the system comprising:

[0024] Cyclohexane feedstock tank,

[0025] A reactor connected to the cyclohexane feedstock tank is used to react cyclohexane with oxygen-containing gas containing CO2.

[0026] Furthermore, the system also includes a collection tank connected to the reactor to receive material containing cyclohexyl hydrogen peroxide.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention improves the yield and selectivity of cyclohexyl hydrogen peroxide by reacting cyclohexane with an oxygen-containing gas containing CO2, solving the problem of low yield in the existing cyclohexane air oxidation method for producing cyclohexyl hydrogen peroxide. Furthermore, the method of this invention is green, environmentally friendly, and efficient, providing excellent raw materials for organic production. Moreover, this invention reduces production costs, requires less equipment investment, and has a simple operation process, making it suitable for continuous industrial production of cyclohexyl hydrogen peroxide via cyclohexane air oxidation. Attached Figure Description

[0029] Figure 1 This is a system schematic diagram of one embodiment of the present invention;

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Cyclohexane feed tank; 2. Cyclohexane feed pipe; 3. Reactor; 4. Gas feed pipe; 5. Tail gas discharge pipe; 6. Synthesis liquid discharge pipe; 7. Collection tank. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0034] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0035] In a first aspect, the present invention provides a method for oxidizing cyclohexane to produce cyclohexyl hydrogen peroxide, comprising the following steps:

[0036] Reacting oxygen-containing gas containing CO2 with cyclohexane yields a material containing cyclohexyl hydrogen peroxide.

[0037] The inventors of this application discovered during experiments that reducing the concentration of O2 can inhibit the further oxidation of cyclohexyl hydrogen peroxide to a certain extent, but the overall yield of cyclohexyl hydrogen peroxide is not improved. However, adding a large amount of CO2 to the inlet gas can significantly inhibit the further oxidation of cyclohexyl hydrogen peroxide and improve the yield.

[0038] In some embodiments, the volume ratio of CO2 to O2 in the oxygen-containing gas containing CO2 is (2-15):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 13:1, 15:1 or any value between them.

[0039] In some embodiments, the volume ratio of CO2 to O2 in the oxygen-containing gas containing CO2 is (3-10):1.

[0040] In some embodiments, the volume concentration of CO2 in the oxygen-containing gas containing CO2 is 30-60%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60% or any value between them.

[0041] In some embodiments, the volume concentration of O2 in the oxygen-containing gas containing CO2 is 3-15%, for example, 3%, 4%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 10%, 12%, 14% or any value between them.

[0042] In some embodiments, the volume concentration of O2 in the oxygen-containing gas containing CO2 is 5-9%, for example, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9% or any value between them.

[0043] In some embodiments, the oxygen-containing gas containing CO2 also includes an inert gas.

[0044] In some embodiments, the inert gas is selected from nitrogen and / or argon.

[0045] In some embodiments, the mass ratio of the oxygen-containing gas containing CO2 to cyclohexane is (3-15):1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1 or any value between them.

[0046] In some embodiments, the mass ratio of the oxygen-containing gas containing CO2 to cyclohexane is (3-8):1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 or any value between them.

[0047] In some embodiments, the reaction temperature is 130-200°C, for example 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or any value between them.

[0048] In some embodiments, the reaction temperature is 150-170°C, for example 150°C, 153°C, 156°C, 159°C, 162°C, 165°C, 168°C or any value between them.

[0049] In some embodiments, the reaction pressure is 0.9-1.5 MPa, for example 0.9 MPa, 1.0 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa or any value between them.

[0050] In some embodiments, the reaction pressure is 1.0-1.2 MPa.

[0051] In some embodiments, the reaction time is 1-20 min, for example 1 min, 5 min, 10 min, 12 min, 15 min, 17 min, 20 min or any value between them.

[0052] In some embodiments, the reaction time is 2-10 min, for example 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min or any value between them.

[0053] In a second aspect, the present invention provides a system for the oxidation of cyclohexane to produce cyclohexyl hydrogen peroxide, which is used in the method described in the first aspect of the present invention, the system comprising:

[0054] Cyclohexane feedstock tank,

[0055] A reactor connected to the cyclohexane feedstock tank is used to react cyclohexane with oxygen-containing gas containing CO2.

[0056] In some embodiments, the system further includes a collection tank connected to the reactor to receive material containing cyclohexyl hydrogen peroxide.

[0057] In some embodiments, the step of preparing cyclohexyl hydrogen peroxide using the above-described system for preparing cyclohexane oxidation includes:

[0058] (1) Cyclohexane is continuously fed into reactor 3 from cyclohexane feed tank 1 through cyclohexane feed pipe 2;

[0059] (2) The oxygen-containing gas containing CO2 is continuously introduced through the gas feed pipe 4 through the bottom of the reactor 3. Cyclohexane reacts with the oxygen-containing gas containing CO2 in the reactor 3 to obtain the material containing cyclohexyl hydrogen peroxide and the tail gas. The tail gas is discharged through the tail gas discharge pipe 5.

[0060] (3) The material containing cyclohexyl hydrogen peroxide enters the collection tank 7 through the synthesis liquid discharge pipe 6.

[0061] In some implementations, the exhaust gas can be returned to reactor 3 to continue the reaction.

[0062] The present invention is further illustrated by the following embodiments, but the present invention is not limited to the following embodiments.

[0063] In this invention, Ar represents argon gas.

[0064] In this invention, the percentage content of gases refers to the volume percentage.

[0065] In the following examples and comparative examples, the feedstock cyclohexane was calculated based on a flow rate of 84 g / min.

[0066] The method for calculating the cyclohexane conversion rate is as follows:

[0067] Cyclohexane conversion rate = (Moles of cyclohexane consumed in the reaction) / (Moles of hexane fed in the reaction) * 100%

[0068] The yield of cyclohexyl hydrogen peroxide is calculated as follows:

[0069] Cyclohexyl hydrogen peroxide yield = (Molar amount of cyclohexyl hydrogen peroxide produced in the reaction) / (Molar amount of cyclohexane in the feed) * 100%

[0070] [Example 1] (Oxidation reaction of 50% CO2-8% O2 gas with cyclohexane) The percentage content of the above gases is the volume concentration.

[0071] The oxygen-containing gas used in Example 1 contains 50% CO2, 8% O2, and the remainder is 42% nitrogen.

[0072] I) If Figure 1 As shown, cyclohexane is continuously fed into reactor 3 from cyclohexane feed tank 1 via cyclohexane feed pipe 2, with a cyclohexane flow rate of 84 g / min;

[0073] II) Oxygen-containing gas containing CO2 enters reactor 3 through gas feed pipe 4 and comes into contact with cyclohexane, heating the reactor to a reaction temperature of 165°C and a reaction pressure of 1.2 MPa. The tail gas is discharged from tail gas discharge pipe 5.

[0074] III) Oxygen-containing gas containing CO2 at a working pressure (1.2MPa) is continuously fed into reactor 3 through gas feed pipe 4 for reaction, with a gas flow rate of 300g / min;

[0075] IV) The material containing cyclohexyl hydrogen peroxide (CHHP) obtained after the reaction enters the collection tank 7 from the synthesis liquid outlet pipe 6, and the reaction residence time is calculated to be 5 min;

[0076] V) Stop feeding and end the reaction after a total feeding time of 30 minutes.

[0077] The cyclohexane consumption was calculated by analyzing the concentration of cyclohexane in the synthesis solution effluent using gas chromatography, and the cyclohexyl hydrogen peroxide production was calculated by analyzing the concentration of cyclohexyl hydrogen peroxide using potassium iodide titration. Combined with the cyclohexane feed rate, the cyclohexane conversion rate and cyclohexyl hydrogen peroxide yield were calculated to be 10.5% and 2.06%, respectively.

[0078]

Example 2-11

[0079] The steps are the same as in Example 1, and the operating conditions are shown in Table 1 below.

[0080] Comparative Examples 1-3

[0081] The steps are the same as in Example 1, and the operating conditions are shown in Table 1 below.

[0082] Table 1

[0083]

[0084]

[0085] As shown in Table 1, compared with the air oxidation method in the prior art, the present invention significantly improves the yield and selectivity of cyclohexyl hydrogen peroxide by reacting cyclohexane with oxygen-containing gas containing CO2.

[0086] Furthermore, by controlling the volume concentration ratio of CO2 to O2 in the oxygen-containing gas containing CO2 to be (2-15):1, preferably (3-10):1, the present invention can further improve the conversion rate of cyclohexane and the yield of cyclohexyl hydrogen peroxide.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for oxidizing cyclohexane to produce cyclohexyl hydrogen peroxide, comprising the following steps: Reacting oxygen-containing gas containing CO2 with cyclohexane yields a material containing cyclohexyl hydrogen peroxide.

2. The method according to claim 1, characterized in that, In the oxygen-containing gas containing CO2, the volume ratio of CO2 to O2 is (2-15):1, preferably (3-10):

1.

3. The method according to claim 1 or 2, characterized in that, The volume concentration of CO2 in the oxygen-containing gas containing CO2 is 30-60%.

4. The method according to any one of claims 1-3, characterized in that, In the oxygen-containing gas containing CO2, the volume concentration of O2 is 3-15%, preferably 5-9%.

5. The method according to any one of claims 1-4, characterized in that, The oxygen-containing gas containing CO2 also includes an inert gas, preferably selected from nitrogen and / or argon.

6. The method according to any one of claims 1-4, characterized in that, The mass ratio of the oxygen-containing gas containing CO2 to cyclohexane is (3-15):1, preferably (3-8):

1.

7. The method according to any one of claims 1-4, characterized in that, The reaction temperature is 130-200℃, preferably 150-170℃.

8. The method according to any one of claims 1-4, characterized in that, The reaction pressure is 0.9-1.5 MPa, preferably 1.0-1.2 MPa.

9. The method according to any one of claims 1-4, characterized in that, The reaction time is 1-20 min, preferably 2-10 min.

10. A system for the oxidation of cyclohexane to prepare cyclohexyl hydrogen peroxide, used in the method of any one of claims 1-9, said system comprising: Cyclohexane feedstock tank, A reactor connected to the cyclohexane feedstock tank to react cyclohexane with oxygen-containing gas containing CO2; Preferably, the system further includes a collection tank connected to the reactor to receive material containing cyclohexyl hydrogen peroxide.

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